1. Field of the Invention
The present invention relates generally to roll testers and, more particularly, to a surface durability roll tester for simulating gear teeth geometry and kinematics.
2. Description of the Related Art
It is known to provide a roll tester. A roll tester is a machine that is used to evaluate the effects of materials, manufacturing processes and operating conditions on the performance of components that are subjected to rolling, sliding or combinations of rolling and sliding contact with another component. For example, gears and bearings are components that are subjected to rolling and sliding contact with another component. The roll tester typically includes two cylindrical rolls, which are driven independently at two different speeds. The contact pressure between the two rollers is accomplished by applying a load on each end of one of the rollers directed toward the center of the other roller. The speeds and pressure in which the rollers are driven are chosen to simulate a particular operating condition, which is of interest. The speeds of the rollers can be chosen to simulate pure rolling or varying degrees of positive and negative sliding. A test is accomplished by setting the speeds of each roller to obtain the desired sliding and rolling velocity and setting the contact pressure to the desired pressure that simulates the conditions under investigation. These test conditions are held constant throughout the test. The test is concluded when a predetermined amount of damage is produced in the rollers.
Although the above roll tester has worked well, it suffers from the disadvantage that the straight cylindrical rolls on the roll tester do not simulate the geometry and velocity of gear teeth. Another disadvantage of the above roll tester is that the straight cylindrical rolls do not allow contact loads to be applied effectively. Yet another disadvantage of the above roll tester is that the straight cylindrical rolls do not accurately simulate the geometry and velocity of gear teeth. Therefore, there is a need in the art to provide an improved surface durability roll tester.